The howitzer-type gun is the central piece of artillery used in military batteries throughout the world. This gun can be fired with great accuracy and at long ranges if the gun is correctly aimed. However, the correct aiming of the gun by a gun operating crew requires substantial and extended training of that crew, not only for accuracy of aiming the gun, but for the rapidity at which that aiming can take place.
As can be appreciated, in a training exercise, an instructor could visually evaluate each of the aiming settings, as those settings are made, but this would require an interruption of the crew's aiming exercise while observations of a particular setting and subsequent settings are made. This would destroy the rapidity aspect of proper training and not simulate combat conditions.
To avoid such interruption of the crew in training, for some time the art has provided a series of howitzer instrumenting apparatus which is embedded into the sighting devices of the howitzer in a more or less permanent fashion, i.e. it is time consuming and difficult to attach and detach that apparatus. That embedded apparatus is capable of determining the settings and other parameters made by a training crew and substantially instantaneously conveying that information to the instructor for evaluation purposes.
However, as can be easily appreciated, since those prior art devices were substantially embedded in the howitzer gun sighting devices so as to modify a particular gun for training purposes or in the sighting devices of a simulated gun, i.e. a trainer, and since for economy a limited number of howitzers can be justifiably so modified or trainers constructed, a substantial problems existed in either transporting a crew for training to such modified gun or trainer or transporting such modified gun or trainer to a crew for training. This is particularly true when the training of the crew is in the field, and, therefore, it is necessary to transport such modified gun or trainer from one training field location to another training field location. This not only severely limits the time available for training on the modified gun or trainer, but the cost of transporting the crew/gun/trainer is substantial. Further, the cost of so modifying such a gun or trainer is quite high, and such modified gun, usually, can no longer be used for ordinary military (combat) purposes.
In this latter regard, a trainer, typically, will be an actual or slightly modified turret of a mobile howitzer gun, and, therefore, transportation thereof, as noted above, is at least as difficult as an actual mobile howitzer gun. Also, while the prior art devices do not deactivate an actual howitzer gun such that it could not be aimed and fired, the embedded prior art apparatus, along with its associated wiring and controls, gave a different appearance to a gun crew which could cause confusion on the part of a crew not familiar with such embedded apparatus.
Further, since detaching the embedded apparatus is both time consuming and complex, once an actual howitzer gun was so modified, a substantial reluctance to detaching the apparatus arose because of the risk that such attachment and detachment of the embedded apparatus could result in the aiming devices of the howitzer gun not being fully correctly reassembled and could cause aiming problems in subsequent combat use.
Further, such embedded apparatus was also used to test new procedures for operation, including aiming, of the howitzer gun, which might be required from time to time, even in field or even in combat use. Thus, detaching the embedded apparatus for field or combat use resulted in a necessity for reattaching the apparatus for such testing purposes, and each attachment and detachment not only takes the gun out of service for the time periods required therefor, but increased the above-noted risks.
While the foregoing is not a problem to the above extent with a trainer, in certain training exercises, the embedded apparatus interfered therewith and, thus, on occasion the detaching and subsequent re-attaching of the apparatus, along with the above-noted risk of imperfect reassembly of the aiming devices, was required.
It can therefore be seen that the problems associates with the prior art embedded apparatus are substantially common to both an actual howitzer gun and a trainer. Thus, the present invention is directed to both, and the term "howitzer gun" as used hereinafter, including the claims, is defined to mean an actual howitzer gun and a simulating trainer therefor.
Accordingly, it is clear that there is a need in the art for more appropriate means of training a crew for aiming and firing a howitzer gun, or a like gun, but no art has been developed to supply that need. For example, U.S. Pat. No. 5,215,462 uses sensors for determining the position of a simulated weapon relative to a target when a trigger sensor indicates that the simulated weapon's trigger has been pulled. While such sensors could be mounted and dismounted for use on different simulated weapons, the system of that patent is applicable only to simulated weapons and therefore would be of little value in realistic training of a crew on an actual howitzer gun.
Another approach in the art is disclosed in U.S. Pat. No. 3,798,795, where a target flight path is measured by an optical sensor and a radio ranging apparatus. Sensors determine the aim of the weapon for evaluating the accuracy of that aim in relation to the determined flight path of the target. However, that system is similar to those described above, in that the various sensors and other data acquisition devices are essentially permanently affixed to the weapon, other than the optical sensor and radio ranging apparatus. Accordingly, this approach of the prior art is also not satisfactory for training on howitzer guns for the reasons noted above.
Another approach in the art for gunnery training is illustrated by U.S. Pat. No. 2,795,057, where an image projector presents a realistic shadow image on a spherical screen using a model fighter airplane. The fire control system of the trainer is the same fire control system used in an aircraft to which the trainees are to be assigned. However, the sighting stand and the trainer itself are but a model of the weapon, and no actual field conditions can be imposed in that training exercise. Thus, here again, this approach of the prior art is unsatisfactory for present purposes.
On the other hand, U.S. Pat. No. 4,923,402 suggests the approach of a long range light pen to measure sighting accuracy, but since howitzers are not generally fired by line of sight, that approach is also inapplicable to the present situation.
Finally, an approach in the art is illustrated by U.S. Pat. No. 5,201,658, where an artillery simulator apparatus is provided. While the simulator attempts to simulate the action of the artillery piece and the various parameters of the firing, including aiming, this approach, nonetheless, is a simulator and not applicable to field use with a howitzer gun. Thus, here again, that approach in the prior art is not viable to the present situation.
In the above regards, the aiming device of a howitzer gun sets the gun deflection (azimuth) and elevation for firing a projectile at the correct angle for hitting the target. That aiming device has a "pantel" (a conventional shortened term for panoramic telescope), which provides a sight picture capable of viewing a distant reference collimator for alignment of the pantel with the collimator. The panoramic telescope or "pantel" must first be aligned with the reference collimator when the collimator is placed some distance from the howitzer. The pantel must also be levelled and, for accurate fire, must be levelled on two axes. By the gunner sighting the pantel on the collimator, the pantel can be aligned with that collimator, so that a precise position of the gun along the sight line with the collimator is determined. By then entering a desired deflection (azimuth) value into a pantel deflection setting means, the gun barrel, by returning the turret to that sight line, as explained more fully below, may be then positioned at that correct deflection.
At the same time, in order to correctly lay the howitzer's elevation on the target, the assistant gunner enters the desired elevation into a levelled quadrant setting means, and this causes a rotatable level indicator to be displaced from level. By returning to level, the gun barrel is elevated at the correct angle for accurately hitting the target, as explained more fully below. The quadrant must be first levelled, and the quadrant level indicator for indicating the level of the quadrant is used for this purpose. Here again, for accurate fire, the quadrant must be levelled on two axes, i.e. the level and the cross-level, similar to that mentioned above in connection with the pantel.
The foregoing aiming steps, as briefly described above, are carried out simultaneously by the gunner and assistant gunner, and in view of the required rapidity of fire in combat, those steps must be very quickly and accurately completed. Thus, in a training exercise, it is absolutely necessary for any evaluation of the performance of a crew not to interfere with that rapid aiming of the gun by the gunner and assistant gunner, which interference would be required for an evaluator to visually observe each setting or levelling as it occurs. Furthermore, for accurate training, any evaluation means must not introduce any devices which are substantially different from the actual aiming devices of the howitzer gun, since, otherwise, the training devices would not accurately simulate the motions and actions taken by the training crew when operating the actual aiming device. In addition, for realistic training, the evaluator should not be near the crew, so as to not interfere with the usual operation of the crew or to impose any nervousness thereon. Thus, the evaluator and any devices used for evaluation should be remote from the howitzer on which the training takes place.
Further, as briefly noted above, an important step in aiming a howitzer is that of aligning the pantel with the collimator by the gunner viewing the collimator in a sight picture of the pantel. The prior art devices had no means of remotely evaluating the position of the collimator in that sight picture, and, hence, an important part of the training exercise could not be remotely evaluated or evaluated without interrupting the training exercise.
Accordingly, it has been quite evident to those skilled in this art that the difficulties described above in connection with training a howitzer crew have not been overcome by the art and that there is a need for obviating those difficulties for the efficient training of a howitzer crew.